Aluminum warm forming oven and production line

A multi-window platen oven for simultaneously heating a plurality of blanks, for example aluminum blanks, before forming the heated blanks in a production line is provided. The oven includes a plurality of vertically aligned shelves disposed in an existing press assembly so that no additional floor space is required. The shelves are attachable to an upper press bed and one another. The upper press bed lifts the attached shelves to present an open window for receiving an unheated blank and/or removing a heated blank from the oven. The remaining windows remain closed and continue heating while the blanks are transferred to and from the oven. After closing the one open window, another window opens to receive another unheated blank and/or remove another heated blank. Thus, the multi-window platen oven continuously provides blanks which are ready for warm or hot forming.